Ma. Monsoor et al., Improved method for determination of pectin degree of esterification by diffuse reflectance Fourier transform infrared spectroscopy, J AGR FOOD, 49(6), 2001, pp. 2756-2760
An improved method for the determination of pectin degree of esterification
(DE) by diffuse reflectance Fourier transform infrared spectroscopy (DRIFT
S) was developed. Pectin samples with a range of DE as determined by gas ch
romatography were used for developing a calibration curve by DRIFTS. A line
ar relationship between the DE of pectin standards and FTIR peak ratio for
ester carboxyl peak area to total carboxyl peak area was found (R-2 = 0.97)
. Pectin DE of various samples was calculated from the linear fit equation
developed by DRIFTS. Accuracy of the DRIFTS method was determined by compar
ing the DE values of four commercial pectins obtained by DRIFTS methods to
the values obtained by the gas chromatography method. Greater precision was
obtained for the FTIR measurement of test pectin samples when the ester pe
ak ratio was used relative to the ester peak area.